The present invention relates to an inductively-heated gallet or godet for the treatment of synthetic fibers or yarns and is directed to a structure which is simultaneously advantageous for installation, set-up, operation and maintenance. It should be noted that a textile machine usually has a multiplicity of such godets which are supplied with operating parameters by a control computer for speed and temperature.
From EP 0 235 505 B1 and EP 0 424 867 B1 it is known to cool the motor, inductor and bearings of inductively heated godets with air or liquid. For numerous industrial purposes, so-called integral motors comprised of a motor and frequency converter have been provided (compare Journal xe2x80x9cPRODUKTIONxe2x80x9d of April 2 1998, No. 14, page 15). A blower cooling for a godet unit, motor and converter is described in DE 197 26 258 A1 where the frequency converter is encapsulated in a housing in a heat transfer state in which, for heat dissipation, the surface provided with cooling ribs is cooled by a blower. For this purpose, the converter housing is provided with a common axis with the motor and on the opposite side of the motor from that of the godet in a cup-shaped godet housing which also encloses the motor and in whose bottom region a blower impeller separately driven by a fan motor displaces cooling air initially over the converter housing and then over the godet motor.
A godet assembly according to the invention can be affixed on a machine frame of a yarn processing apparatus and is provided with an inductively heatable godet and a drive motor, whereby a frequency converter for the motor, a controller serving as a temperature regulator for the heater as well as monitoring devices for the godet for the heater and/or for the motor are integrated in the godet assembly.
With the invention, a compact and integrated godet assembly is obtained which is especially suitable both for high thread load (thermal loading) and high speed. The important advantage of the assembly of godet, frequency converter/drive, temperature regulator and monitor device to an integrated unit resides in that no separately conditioned space is required as the control and circuitry closet and the cabling costs are sharply reduced. The overall unit, i.e. the mechanics of the motor drive as well as the heat control, is completely testable before it is installed in the textile machine so that long start-up times of the machine and possible installation defects are avoided. In case a unit replacement is required, the production fall-out time is significantly reduced because the replacement unit can be fully tested mechanically and electrically before installation. Environmental influences are largely excluded because of the compact construction of the electronic circuitry in the unit itself and the suitable cooling thereof. In addition, the incorporation of the electronic circuitry directly in the unit allows the measurement and monitoring of additional physical and electrical parameters without requiring therefore expensive cabling. The electromagnetic inertia of the overall system is significantly improved because of the compact construction and the short cables.
The frequency converter, the controller and the monitoring circuitry can be incorporated in a sealed housing which is directly affixed to the godet unit and is electrically connected with it. As the single electrical connection to the exterior, an alternating current terminal for the heating power, a direct current terminal for the converter as well as a data base terminal to a computer can be provided. The godet assembly can have air cooling of the power circuitry. The power circuitry and the controller can be mounted on a heat conductive cooling block which is well conducting and which is in good heat conducting relationship with an outer protective housing. The preferably cylindrical protective housing can be provided with axial cooling ribs. The blower can be arranged as a cooling blower in the axial direction of motor and godet between the drive motor and the cooling block. The blower roller can be affixed to the godet. The godet assembly can also have liquid cooling, the converter and controller are carried by a hollow liquid cooled cooling block. In the axial direction of the motor shaft between the cooling block and godet holder or support flange the motor housing is provided with coolant passages or a coolant annular gap. Further coolant passages can be provided for cooling the shaft bearing. In the inductively heated godet, additional coolant passages and spaces can be provided in the region of the heating inductor and/or the hub of the godet. A bearing housing carrying at least the bearing remote from the motor and can extend into the godet shell and the inductor. The bearing remote from the motor can be located approximately at the center of gravity of the godet. The configuration of the cooling passages is such that the cooling liquid initially flows through the cooling block, then through the motor cooling passages and then through an annular space surrounding the godet hub and then through a cooling passage for the bearing and inductor before it flows to the coolant outlet. The components of the converter can be mounted on a cover plate and the components of the controller can be mounted on the opposite cover plate of a hollow substantially rectangular cooling block. The cooling block can be affixed to the end wall furthest from the godet of the motor housing. Between the cooling block and the wall or ring plate carrying same, a thermal and/or mechanical insulating intermediate layer is provided. The cooling block can be surrounded by a sealed protective hood. The assembly two spaced-apart shaft bearings, and the shaft bearing furthest from the motor is disposed within the integrator and is carried by a bearing housing surrounding shaft, while a support flange which serves to affix the unit on the machine frame extends into the interior of the integrator. The bearing housing can serve simultaneously to support the integrator. The inductor can be comprised of an inductor support tube held by the support flange, an inductor core preferably of electromagnetic sheet surrounding the support tube and an exciting winding on the inductor core.
The inductor support tube and the bearing housing there is an annular gap which is sealed in axial direction on both sides by elastic sealing rings which simultaneously serve as vibration damping between the inductor and the bearing housing. A bearing temperature sensor can be arranged in the region of the bearing furthest from the motor. One of the bearings can be located in the region of the support flange. An asynchronous drive motor which can be used and can be controlled by the controller taking into consideration the slip frequency of the drive motor for simultaneously synchronous speed regulation. The transmission of temperature measurement signals from the godet to the controller is effected by a rotating measuring value transmitter serving as a pulse generator for signals serving for speed regulation. The controller can measure the torque by the slip of the asynchronous motor and thus determines the thread tension.
The monitoring device can monitor, in addition to the godet temperatures, the bearing temperatures and the inductor temperatures also other physical and/or electrical magnitudes like vibration, cooling water and motor temperature, motor current and supplies warning or safety shutdown signals derived therefrom.
A common cooling of the electronic power circuitry, motor, bearings and other parts of the unit, e.g. the inductor, can be carried out in a manner known per se (compare EP 0 424 867) with intrinsic or external ventilation. For this purpose preferably a carrier or cooling body enclosed by a cylindrical housing or housing part is connected to the blower and is constructed to receive the power electronic circuitry and the controller such that this electronic housing lies on the suction side of the blower and the motor as well as its bearing lie on its pressure side. The blower impeller can either be driven by the godet motor (intrinsic ventilation) or by a separate fan motor (external ventilation).
The cooling by means of a cooling liquid, for example, the cold water of a coolant unit, enables cooling of the power electronic circuitry and the controller independently of ambient temperature and the intrinsic heating of the unit. With liquid cooling the godet motor requires no additional drive power for the blower. A common cold water supply for the electronic power circuitry, motor and bearing has a single cold water connection for the unit.